Reversal to air-driven sound production revealed by a molecular phylogeny of tongueless frogs, family Pipidae

<p>Abstract</p> <p>Background</p> <p>Evolutionary novelties often appear by conferring completely new functions to pre-existing structures or by innovating the mechanism through which a particular function is performed. Sound production plays a central role in the behavior of frogs, which use their calls to delimit territories and attract mates. Therefore, frogs have evolved complex vocal structures capable of producing a wide variety of advertising sounds. It is generally acknowledged that most frogs call by moving an air column from the lungs through the glottis with the remarkable exception of the family Pipidae, whose members share a highly specialized sound production mechanism independent of air movement.</p> <p>Results</p> <p>Here, we performed behavioral observations in the poorly known African pipid genus <it>Pseudhymenochirus </it>and document that the sound production in this aquatic frog is almost certainly air-driven. However, morphological comparisons revealed an indisputable pipid nature of <it>Pseudhymenochirus </it>larynx. To place this paradoxical pattern into an evolutionary framework, we reconstructed robust molecular phylogenies of pipids based on complete mitochondrial genomes and nine nuclear protein-coding genes that coincided in placing <it>Pseudhymenochirus </it>nested among other pipids.</p> <p>Conclusions</p> <p>We conclude that although <it>Pseudhymenochirus </it>probably has evolved a reversal to the ancestral non-pipid condition of air-driven sound production, the mechanism through which it occurs is an evolutionary innovation based on the derived larynx of pipids. This strengthens the idea that evolutionary solutions to functional problems often emerge based on previous structures, and for this reason, innovations largely depend on possibilities and constraints predefined by the particular history of each lineage.</p

“Horror, guilt and shame” – Uncomfortable Experiences in Digital Games

Gameplay frequently involves a combination of positive and negative emotions, where there is increasing interest in how to design for more complex forms of player experience. However, despite the risk that some of these experiences may be uncomfortable, there has been little empirical investigation into how discomfort manifests during play and its impact on engagement. We conducted a qualitative investigation using an online survey (N=95), that focused on uncomfortable interactions across three games: Darkest Dungeon, Fallout 4 and Papers, Please. The findings suggest games create discomfort in a variety of ways; through providing high-pressure environments with uncertain outcomes and difficult decisions to make, to the experience of loss and exposing players to disturbing themes. However, while excessive discomfort can jeopardize player engagement, the findings also indicate that discomfort can provide another facet to gameplay, leading to richer forms of experience and stimulating wider reflections on societal issues and concerns

“One of the baddies all along” : Moments that challenge a player’s perspective

Reflection has become a core interest for game designers. However, empirical research into the kinds and causes for reflection within games is scarce. We therefore conducted an online questionnaire where participants (n=101) openly reported perspective-challenging moments within games, their causes, experience, and impact. Where past work has emphasised transformative reflection that changes player’s views and behaviour outside the game, we found that players report predominantly moments of ‘endo’-transformative reflection, which is focused on players’ game-related behaviour and concepts. We further identify some causes of perspective-challenging moments relating to narrative, game systems, game-external sources, and player expectations. Narrative reveals emerge as a key cause of perspective challenge

Smoothness criteria for runway rehabilitation and overlays /

"July 1990."Cover title.Final report.Performed by Surface Dynamics, Inc.Mode of access: Internet